Generally, an integrated circuit comprising a plurality of IC terminals is tested its electronic performances before it is put on the market. In order to test the integrated circuit, the integrated circuit is electrically connected to an electronic circuit comprising a plurality of electronic pads corresponding to the IC terminals of the integrated circuit.
There have been provided a various forms of integrated circuits, such as ball grid array form or fine-pitch ball grid array form. The IC terminals of such the integrated circuit are formed with solder bumps and arrayed at one side of the integrated circuit. Because of the fact that the IC terminals of the integrated circuits are formed with solder bumps, there may be difference in heights among the IC terminals of the integrated circuit. This may cause the problem that some of the IC terminals of the integrated circuit cannot be connected with the corresponding electronic pads of the electronic circuit when the integrated circuit is put on the electronic circuit to have each of the IC terminals face each of the electronic pads. In order to solve the problem, a connector such as an IC socket is used to connect the integrated circuit and the electronic circuit.
There is shown in FIGS. 5 and 6 a first example of a conventional IC socket 190 to connect an integrated circuit 170 and the electronic circuit 180. The integrated circuit 170 has a plurality of IC terminals 171 while the electronic circuit 180 has a plurality of electronic pads 181 each corresponding to the IC terminals 171 of the integrated circuit 170.
As shown in FIG. 5, the IC socket 190 comprises a support portion 191 and a plurality of probe pins 193 each having electrically conductive first and second terminals 194 and 195 at its longitudinal ends. The support portion 191 of the IC socket 190 is formed with a plurality of through bores 192 to have each of the probe pins 193 respectively received therein.
The IC socket 190 is positioned between the integrated circuit 170 and the electronic circuit 180 to electrically connect the integrated circuit 170 and the electronic circuit 180. Then, the integrated circuit 170 is urged toward the electronic circuit 180 by urging means (not shown in the drawings), to ensure the connections between the integrated circuit 170, IC socket 190 and the electronic circuit 180.
FIG. 6 shows one of the probe pins 193 in detail. The probe pin 193 comprises its inside a coil spring 196 having first and second contact balls 197 and 198 at its both ends to be respectively held in contact with the first and second terminals 194 and 195 of the probe pin 193. The first and second terminals 194 and 195 of the probe pins 193 are to be respectively held in contact with the IC terminals 171 of the integrated circuit 170 and the electronic pads 181 of the electronic circuit 180.
The IC socket 190 can accommodate and withstand the force generated by the urging means which is urging the integrated circuit 170 toward the electronic circuit 180, because of the fact that each of the probe pins 193 of the IC socket 190 has the coil spring 196.
The conventional IC socket 190, however, cannot be conform to a recently designed high frequency integrated circuit having extremely short cycle pitch, with an electronic circuit for testing the integrated circuit.
As shown in FIG. 6, the IC socket 190 is positioned between the integrated circuit 170 and the electronic circuit 180 to electrically connect the integrated circuit 170 and the electronic circuit 180 and to allow the electronic current to flow in the coil spring 196 of the probe pin 193. As is understood from the drawing, the distance between the integrated circuit 170 and the electronic circuit 180 by way of the coil spring 196 through which the current flows is much longer than the distance in straight line between the integrated circuit 170 and the electronic circuit 180. This difference in distance can cause errors on the results of the test especially when the electronic performances of the high frequency integrated circuit are tested.
Furthermore, as coils are known to generate electromagnetic induction, the coil spring 196 as being a coil may cause an undesirable effect on the results of the test.
Another example of a conventional IC socket 260 to connect an IC 240 and an electronic circuit 250 is shown in FIGS. 7 and 8.
The IC socket 260 comprises a support portion 263 having a certain thickness and being formed with upper and lower surfaces each extending parallel relationship with each other, and a plurality of first and second terminals 261 and 262.
FIG. 8 shows a part of the IC socket 260 in detail. The support portion 263 is formed with an insulating rubber 265 such as a silicon rubber and a plurality of electrically conductive wires 264 each being fitted in the insulating rubber 265 with inclined relationship to the upper and lower surfaces of the support portion 263 to be spaced apart from each other at a predetermined small pitch.
The first and second terminals 261 and 262 are respectively disposed at the upper and lower surfaces of the insulating rubber 265 to be correspondingly connected by some of the electrically conductive wires 264. Because of the fact that the electrically conductive wires 264 are spaced apart from each other at the predetermined small pitch, each of the first and second terminals 261 and 262 of the IC socket 260 is insulating from the adjacent first and second terminals 261 and 262, respectively.
As shown in FIG. 8, the IC socket 260 is positioned between an integrated circuit 240 and an electronic circuit 250 to electrically connect the integrated circuit 240 and the electronic circuit 250. Then, the integrated circuit 240 is urged toward the electronic circuit 250 by urging means (not shown in the drawings), to ensure the connections between the integrated circuit 240, IC socket 260 and the electronic circuit 250.
The IC socket 260 can accommodate and withstand the force generated by the urging means which is urging the integrated circuit 240 toward the electronic circuit 250, because of the fact that each of the electrically conductive wires 264 is fitted in the insulating rubber 265 with inclined relationship to the upper and lower surfaces of the support portion 263.
The conventional IC socket 260, however, cannot be conform to a recently designed high frequency integrated circuit having a lot of IC terminals in a small space, with an electronic circuit for testing the integrated circuit. The IC socket needs to have a lot of terminals in a small space in order to connect such the recently designed high frequency integrated circuit with an electronic circuit.
Because of the fact that the electrically conductive wires 264 are fitted in the insulating rubber 265 with inclined relationship to the upper and lower surfaces of the support portion 263, as shown in FIG. 8, the first and second terminals 261 and 262 are respectively positioned at upper and lower surfaces of the support portion 263 with inclined relationship with each other to have some of the electrically conductive wires 264 put therebetween. Therefore, it is difficult for the IC socket 260 to have a lot of terminals in a small space.
Furthermore, as is understood from FIG. 8, the length D2 of each of the electrically conductive wires 264 through which the current of electricity is allowed to flow is longer than the thickness D1 of the support portion 263. This difference in distance can cause errors on the results of the test especially when the electronic performances of the high frequency integrated circuit having extremely short cycle pitch, are tested.